From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> Subject: mm/mmap: add inline munmap_vma_range() for code readability There are two locations that have a block of code for munmapping a vma range. Change those two locations to use a function and add meaningful comments about what happens to the arguments, which was unclear in the previous code. Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@xxxxxxxxxx Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 48 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 15 deletions(-) --- a/mm/mmap.c~mm-mmap-add-inline-munmap_vma_range-for-code-readability +++ a/mm/mmap.c @@ -575,6 +575,33 @@ static inline struct vm_area_struct *vma return vma->vm_next; } + +/* + * munmap_vma_range() - munmap VMAs that overlap a range. + * @mm: The mm struct + * @start: The start of the range. + * @len: The length of the range. + * @pprev: pointer to the pointer that will be set to previous vm_area_struct + * @rb_link: the rb_node + * @rb_parent: the parent rb_node + * + * Find all the vm_area_struct that overlap from @start to + * @end and munmap them. Set @pprev to the previous vm_area_struct. + * + * Returns: -ENOMEM on munmap failure or 0 on success. + */ +static inline int +munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len, + struct vm_area_struct **pprev, struct rb_node ***link, + struct rb_node **parent, struct list_head *uf) +{ + + while (find_vma_links(mm, start, start + len, pprev, link, parent)) + if (do_munmap(mm, start, len, uf)) + return -ENOMEM; + + return 0; +} static unsigned long count_vma_pages_range(struct mm_struct *mm, unsigned long addr, unsigned long end) { @@ -1721,13 +1748,9 @@ unsigned long mmap_region(struct file *f return -ENOMEM; } - /* Clear old maps */ - while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, - &rb_parent)) { - if (do_munmap(mm, addr, len, uf)) - return -ENOMEM; - } - + /* Clear old maps, set up prev, rb_link, rb_parent, and uf */ + if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf)) + return -ENOMEM; /* * Private writable mapping: check memory availability */ @@ -3063,14 +3086,9 @@ static int do_brk_flags(unsigned long ad if (error) return error; - /* - * Clear old maps. this also does some error checking for us - */ - while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, - &rb_parent)) { - if (do_munmap(mm, addr, len, uf)) - return -ENOMEM; - } + /* Clear old maps, set up prev, rb_link, rb_parent, and uf */ + if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf)) + return -ENOMEM; /* Check against address space limits *after* clearing old maps... */ if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) _
